PROCEEDINGS 
ROYAL SOCIETY OF EDINBU 
SESSION 1921-22 
Part II] 
VOL. XLII, 
[Pp. 129-256 
CONTENTS. 
NO. PAGE 
X. On the Quantum Mechanism in the Atom. By Professor E. T. 
Whittaker, F.R.S., 129 
{Issued separately June 2, 1922.) 
XI. Note on Professor Whittaker’s Paper ‘‘ On the Quantum 
Mechanism in the Atom.” By Sir J. Alfred Ewing, 
K.C.B., E.R.S., 143 
{Issued separately June 6, 1922.) 
XII. The Concomitants (including Differential Invariants) of Quad- 
ratic Differential Forms in Four Yariables. By Professor 
A. R. Forsyth, Sc.D., F.R.S., Hon. F.R.S.E., Imperial 
College of Science and Technology, S.W., . . . 147 
{Issued separately July 4, 1922.) 
XIII. The Magnetic Character of the Quantum. By H. Stanley 
Allen, M.A., D.Sc., ........ 213 
{Issued separately July 4, 1922.) 
XIV. Note on Professor Whittaker’s Quantum Mechanism in the 
Atom. By Dr R. A. Houstoun, 221 
{Issued, separately July 4, 1922.) 
XV. The Importance of Professor Whittaker’s Atomic Model and 
of other Atomic Models. By Professor W. Peddie, . . 223 
{Issued separately July 4, 1922.) 
[Continued on page iv of Cover. 
EDINBURGH: 
Published by ROBERT GRANT & SON, 126 Princes Street, and 
williams & NORGATE, 14 Henrietta Street, Covent Garden, London, W.C. 2. 
Price Fourteen Shillings. 
